How Does A Dirt Bike GearBox Work

Being a dirt bike lover you would also have an interest in getting all kind of information which are associated with a Dirt Bike. What makes unique a Dirt Bike from regular bikes that is the most important thing to understand. So here in this post, we will be talking about how does a Dirt Bike gearbox works?

It can be really annoying if while riding something broken inside the bike. And in that condition, if you know the working process of all the tools then you can easily understand your problem with the bike.

So in my point of view just don’t be a rider you also need to be a good mechanic for your own dirt bike. It can really make you feel happy when you can come out of a situation where no one is there to help you. But before understanding how does a gearbox work you need to understand what is there inside a gearbox and what is it’s working principle.

If you don’t know about how to whip a dirt bike then it can be more fun for you if you know this.

What is a Gearbox in a Dirt Bike?

When we talk about the gearbox it can be really confusing for a beginner because there are a lot of synonyms that are being used by engineers and designers. The gearbox is also named as gear reducer and gear head.

So now here we will talk about the basic definition of a gearbox and that is “Gearbox is a component that consists of a series of integrated gears. It is packed inside a housing.”

Mostly gearbox works like a system of gears that functions to alter the torque between a driving component and a load. Here we suppose a motor as the driving component.

The gears which are used inside a gearbox can be of different types such as Bevel gears, Spiral gears, Planetary gears, and worm gears. The gear is mounted on a shaft. This shaft is rotated by a rotating bearing. It is a mechanical method that is used to transfer the energy from one component to another component which results in an increase in torque and decrease in speed and vice versa.

Types of gearbox:

  • Constant-mesh gearbox
  • Sliding mesh gearbox
  • Synchromesh gearbox

Structure of a Gearbox

A gearbox is consisting of a driving gear with a particular diameter connected to the driving mechanism linked to another gear of larger and smaller diameter coupled to a driven mechanical load.

If the driving gear is linked with the smaller gear of size then the driving mechanism will have a higher speed than the driving one. And if the diameter will be larger of the gear than the speed of the driving mechanism will be smaller than driven one.

Gearbox system and mechanism is used for achieving the speed and torque. Suppose if the dirt bike is going to move on an upward path then it will require higher torque and that can be achieved by lowering the speed at the same power. When the bike will require less torque then the speed can be increased with the same power.

How does a Dirt bike Gearbox Work?

How Does A Dirt Bike GearBox Work

In a gearbox, there are different sizes of gears are assembled. For getting different speeds it needs to have gears of many sizes. While running a bike sometimes it requires high torque and in that situation for getting high torque speed is decreased and torque is increased. And when a rider wants to increase speed then torque is decreased and hence speed increases.

For example when the slop is high while riding then bike requires high torque for this and then you need to shift to first or 2nd gear then your speed is low and torque is increased. Inside a gearbox, the biggest size of the gear produces maximum torque and it is the first gear. And then as you go up like 2,3,4 in sequence the gear sizes will decrease in a row.

In simple words when the engine starts it transmits the power to driving gear which is mounted on a shaft and then according to your choice of gear driving gear engages with driven gear and then this rotates and hence connected wheels also rotate.

Gearbox working principle:

If we talk about the gearbox then you need to know that there are 2 sets of gears in a conventional gearbox. One of them is input and another one is output.

Then output gears are mounted on the counter-shaft and creating it a single unit. This counter-shaft drives the individual gears on the main shaft. Hence shaft here rotates on the bearings. The gearbox arrangement passes the power to drive the wheels. The speed depends upon the gear which is selected and engages in the main shaft.

When you push the lever of gear then according to your selection that gear locks to the main shaft and rotates it by giving its power. Hence the main shaft rotates at the speed of the engaged gear which you have selected and this provides the output power according to the engaged gears ratio.

We are here giving the information about the gear ratio in a gearbox. So first of all, you need to understand what is the gear ratio.

What is Overdrive?

In short, the top gear or the final gear is the smallest in size. This gear provides the minimum traction and maximum speed. When we say overdrive for a gearbox means…..

In simple words, the gear rotates faster than the speed of the engine which provides a better efficiency to run the vehicle fast.

In the advanced technology Dirt Bikes, more than one Overdrive gears used to and it’s normal. Hence the dual Overdrive provides better efficiency and higher speed in a Dirt Bike. Overdrive means the output will be higher than its input.

As we will talk about gear ration then you can clearly understand it. Larger gears provide less speed but a higher traction power ride.

What is the Gear Ratio?

Gear Ratio is defined as the ratio between the input and output gears. As we have already discussed there are two types of gears work in a gearbox that is driving gear and driven gear which defines the ratio. The input gears get the rotation from the engine and they rotate the output gears when they turn and the wheels rotate. The ratio of the number of rotation of earth put gear with the number of rotation of input gear is called the gear ratio.

Formula to understand gear ration in terms of the number of teeth in a gear.

Gear Ratio = Number of teeth of output gear/Number of teeth of the input gear

Suppose if there are two gears input and output then, No of teeth in input gear=40, No of teeth in output gear=120

Then Gear ratio = 120/40 = 3:1 which means when the input gear (driving) rotates 3 times then output gear (driven) will complete one rotation.

How many gears inside a Dirt bike Gearbox

When we talk about the gears in dirt bikes then it is there with different models bike. But most of the bikes come with 5 gears. Now the latest model bikes are coming with 6 gears in it.

Almost all dirt Bikes have the same arrangement of gears which is first gear at the bottom and when you to shift gears after this then neutral, 2nd and so on. If you don’t know how to find the Neutral in a dirt bike then with the article you can easily solve this issue.

  • Sixth Gear
  • Fifth gear
  • Fourth gear
  • Third gear
  • Second Gear
  • Neutral
  • First gear

Gearbox: Speed vs Torque

If you are a dirt bike rider then you can understand the importance of speed and traction both because this both are really essential for driving. The gear inside a gearbox provides you the power to decide on what speed you want to drive.

According to the condition of the track, you choose the gear. There are many times you need to climb a track which is higher and have a slope then you need to shift into the first or second gear to provide maximum torque that will pull your bike upward.

But in a flat track, you can increase your speed by shifting into the fifth or sixth gear. The number of gears inside a gearbox gives you a collective combination of torque and speed. Dirt bike helps you drive by your decision to get 100% of output according to the situation. You can ride your bike in a sloppy surface taking throttle using first or second gear.

For bikes which gears are used?

  • Sliding mesh
  • Sliding Mesh is Generally used in two-wheeler/bikes.

Final words

Just riding is not enough for a beginner but understanding all the systems of a two-wheeler is very important. It can be an extra advantage if you understand all the system and its processes. So here in this article, we have discussed how does a Dirt Bike gearbox work?

I hope this article has given you enough information which can guide you to understand it properly and understand the process of working for a gearbox. If you really like this post and want to support us then please do share with your friends and also subscribe to our newsletter.


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